The assembly of molecular genetic technologies developed for human genetic analysis have been applied to a description of free-ranging populations of endangered species. The goals include: 1) assessment of overall genetic diversity as a reflection of historic present and future demography of the species; 2) detection of population partitions and substructures reflecting geographic isolation over increasing periods; 3) taxonomic inference based upon genetic distinctiveness of species; 4) recognition of perturbations of mating structure; and 5) combining population genetics disposition with infectious disease history to assess the consequences of ongoing genomic interactions. The tools for genomic description used include mitochondrial DNA sequence determination, short tandem repeat polymorphism (microsatellite), SRY - Y chromosome gene sequence analysis, major histocompatibility complex genes, and population genetic theory. The methods have been used to describe species population status of large natural population samples of puma (Puma concolor), ocelot (Leopardis pardalis), margay (Leopardus wiedii), tiger (Panthera tigris), leopard (Panthera pardus), and giant panda (Ailuropoda melanoleuca). The results of each offer a novel look at the survival strategies evolved in these species during their natural history.